analgesic vs tranquilizer

analgesic

noun
  • Any medicine, such as aspirin, that reduces pain, especially without inducing a loss of other sensation. (Contrast anesthetic.) 

adj
  • Acting to relieve pain; being an analgesic. 

  • Unable to feel pain. 

tranquilizer

noun
  • A drug used to reduce anxiety or tension. 

  • That which tranquillizes or soothes. 

How often have the words analgesic and tranquilizer occurred in a corpus of books? (source: Google Ngram Viewer )